FIELD OF THE INVENTION
This invention relates to a molten carbonate type fuel cell.
The construction of the conventional fuel cell of this type is as shown in FIG. 2 of the accompanying drawing.
As can be seen from the drawing, the molten carbonate type fuel cell using, for example, alkali metal carbonate as an electrolyte is generally constructed with an electrolytic layer 1 composed of an electrolyte and a substance which is inactive to the electrolyte; a fuel electrode 2 and an air electrode 3, both being juxtaposed to and in contact with the electrolytic layer in a manner to sandwich the same between them; a gas chamber 7 to the side of the fuel electrode 2, which comprises a fuel electrode side current collecting plate 4 for collecting electric current from the fuel electrode, physically supporting the structural members of the cell, and causing the reactive gas to flow, a gas flow passage plate 5, and a separator 6a with its surface being opposed to the fuel electrode 2; and another gas chamber 10 to the side of the air electrode 3, which comprises an air electrode side current collecting plate 8, a gas flow passage plate 9, and a separator 6b with its surface being opposed to the air electrode 3. Heretofore, the air electrode side gas chamber 10 is constructed with stainless steel (for example, "SUS316L"). However, the corrosion-resistant property of the stainless steel is not sufficient against the electrolyte which has exuded from the electrolytic layer 1 with the consequence that the stainless steel reacts with the electrolyte to cause the main consumption of the Li.sub.2 CO.sub.3 of the electrolyte. In spite of such drawback in the conventional fuel cell, the present situation is such that no sufficient measures have: been taken to solve the problem of this Li.sub.2 CO.sub.3 consumption.
FIG. 3 is a graphical representation showing changes, with a lapse of time, in the quantity of the electrolyte to be consumed by its reaction with the structural members of the air electrode side gas chamber 10 per effective area (1 cm.sup.2) of the electrolytic layer in the conventional fuel cell.
Since the conventional molten carbonate type fuel cell is constructed as described above, it has the problem such that the reaction between the structural members of the air electrode side gas chamber and the electrolyte which has exuded from the electrolytic layer brings about consumption of the electrolyte necessary for the cell operation, whereby the battery characteristic lowers with a lapse of time. Thus, the conventional fuel cell had its own inherent problem that the above-described disadvantages should le eliminated.
The present invention has been made with a view to solving the above-mentioned problem, and aims at providing an improved molten carbonate type fuel cell with a stabilized battery characteristic over a long period of time by replenishing the electrolyte which has been consumed, and maintaining the electrolyte at a consistent composition.